Joist sizes in loft

michaels

Thinking of adding a room to the loft with velux windows - with no dormer head height will be limited so want to minimize joist sizes. There will be 2 steels each 2m away from the existing house central wall. It appears that 4by2 C24 timber at 400mm spacing will be sufficient if the span is taken as the distance from the centre wall to the steels but much larger if the span is between the two steels (4m) - does anyone know if the 1-brick centre internal wall can be considered supporting?

(I would probably add a 25mm wall plate to the top of the existing wall to give clearance from the existing ceiling and then use hangers to support the joists at the steels.)

MX5huggy

Get your Structural Engineer the did the Steel calcs to confirm.

deano72_2

like ^^^ said,i had one survey my loft for a conversion,£135 & plan with the exact calcs sizes & plan of what & where.its best to get it correct & get a building inspecter to sign it off